Jarrod Parker was one of the top young starters in baseball even after Tommy John surgery in 2009, but now he faces a much more difficult task - coming back from a second such procedure.

The A's projected Opening Night starter will miss the entire season with a torn ulnar collateral ligament that will be repaired next week. Dr. James Andrews, who performed Parker's first surgery, will conduct the second next Tuesday in Pensacola, Fla.

"You feel for Jarrod having to get this a second time," catcher Stephen Vogt said. "I can't imagine what he's going through. It's terrible news. I'm so sad for him. And then you talk about what this means for us - he's our unspoken ace.

"Losing a guy of his ability, it's a hit. We are deep, but it's not a good situation."

The odds of a full recovery to previous performance levels are significantly reduced after a second elbow-ligament-replacement surgery. The success rate for a first procedure is generally estimated to be 80 percent or better, but the odds of returning to past form after a second surgery drop to about 40 percent.

Former Giants reliever Brian Wilson is among those to successfully come back from a second surgery. Former A's reliever Jason Isringhausen had the surgery three times in his career and continued to pitch. In general, relievers have fared better with second procedures than have starters.

"Unfortunately, there are more data points on this than there were four years ago," assistant general manager David Forst said. "In the last week, it's come up a number of times. It's hard to predict right now, you don't know the recovery rate on guys with a second Tommy John."

There has been a rash of second Tommy John surgeries recently, with more expected this week: Atlanta's Kris Medlen saw Andrews on Monday and needs the procedure again, and Brandon Beachy, Medlen's teammate, is expected to be in the same boat.

Parker, 25, had been dealing with forearm tightness late last season. He started Game 3 of the ALDS but would not have pitched in the ALCS had the A's advanced. Recovery time is typically 12 to 18 months for a first procedure, but can take longer for a second.

"The first thing in these situations is you feel bad for Jarrod," Forst said. "He worked hard this offseason after some struggles at the end of the year and was going to be at the top of the rotation. But we can only play the hand that we're dealt."

This is a terrible break for the A's, who have won the AL West the past two seasons and who are expected to contend again this year. As Forst emphasized, this is why the club has assembled pitching depth, and a major reason the team didn't trade lefty Tommy Milone, who has 25 wins over the past two years.

"We've been through enough seasons to know that five starters isn't going to make it," Forst said. "In this case, five didn't make it to Opening Day."

Second baseman Eric Sogard called the Parker news "devastating; most of us consider him our ace. But with this team, we always find a way. Guys will step up."

In addition to losing Parker, the A's will not have A.J. Griffin, their projected No. 4 starter, for more than a month because of flexor tendinitis.

Forst said that Oakland will not look outside the organization for help at this point.

On Monday, Scott Kazmir, now the A's No. 2 starter, was scratched with triceps stiffness, which Forst called "very minor." Kazmir might pitch Tuesday or might skip a turn and throw a bullpen session instead.

Drew Pomeranz is likely to go to Triple-A Sacramento to start in case the A's need another fill-in for the rotation, though he remains in the mix for the final bullpen spot, along with Josh Lindblom and Monday's starter, Joe Savery. Ryan Cook remains a 50-50 proposition for the Opening Night roster as he returns from shoulder tightness.

Briefly:Josh Donaldson (calf) won't play Tuesday but is expected to be in the lineup Wednesday. ... Milone will pitch in a minor-league game Thursday.

A's 6, Cubs 2

Notable: Lefty Joe Savery, making a last-minute start when Scott Kazmir was scratched with minor triceps tightness, allowed two hits and a walk in two innings. He struck out five. ... Yoenis Céspedes, working on a new, shorter swing, hit the ball hard three times in going 1-for-3. He's batting .128. ... Brandon Mosswent 2-for-2 with a double, an RBI and two runs. Moss is 13-for-28 this spring. ... Nick Puntowent 2-for-3 with two RBIs and he's 12-for-32 (.375).

Quotable: "Starting is nerve-racking; the waiting part is a lot different. You don't ease into the game, you just go. ... My slider was as good as it's ever been." - Savery, who has not allowed a run in six appearances and who is in the mix for the final bullpen spot.